1,2-vinyl-polybutadiene has heretofore been produced commercially only in solution, slurry or emulsion processes such as those disclosed in U.S. Pat. Nos. 3,498,963; 3,778,424; 4,182,813;and 5,548,045. There have been numerous problems associated with producing vinylpolybutadiene in these processes: the products are too crystalline or conversely too rubbery; tend to be adversely affected by impurities, particularly moisture, air, and water; require difficult polymerization conditions (e.g., relatively low temperature and/or multiple reactors) for efficient commercial production; incompatibility of solvent medium with catalyst components/combinations; difficulties in controlling molecular weight; contamination with low molecular weight polymers; inability to incorporate a desirable amount of vinyl into the polymer; require a large quantity of catalyst due to low catalyst productivity; low yield of desired product; and so forth. Additionally, these processes are labor and energy intensive, require multiple washing and solvent separation and removal steps, and present environmental concerns. All of which adds to the cost of the product and limits its use and availability on a cost basis in the marketplace.
Finally, the vinylpolybutadiene products produced in these processes are recovered in bales, or bale-like form, such that before an end-user can combine these products with other formulation components, the vinyl-containing polybutadiene products themselves must be first cut, ground and/or pulverized before any significant, subsequent dispersion and distribution in an end-user formulation or processing can occur.
It would be beneficial to conduct a polymerization of vinylpolybutadienes in a gas phase reactor, because such a gas phase polymerization would be advantageous, economical, and inherently safer in that the need to handle and recover large quantities of solvent is eliminated while providing low pressure process operation. However, in view of all of the above-enumerated processing difficulties associated with the production of vinylpolybutadiene in non-gas phase processes, it would be unlikely to expect the production of vinylpolybutadienes in a gas phase process to be possible, much less easy. Rather, one would expect some or many of the same problems associated with non-gas phase processes, as well as problems attributable to gas phase operation. Nor would one expect the product to be readily granular and/or flowable, having an even, fairly homogeneous vinyl microstructure distributed throughout in the polymer.
Surprisingly, the present invention provides such a process and vinylpolybutadiene product.